The increase of crash rates in elderly population can be attributed in some part to the effects of normal aging on cognitive functioning. In the other hand, older drivers are likely to adopt self-regulated driving behaviours, such as driving habits to restrict their exposure to less complex situations. Neuropsychological assessments have shown some efficacy in the field of fitness-to-drive screening of older drivers suffering from neurological disorders. This thesis aims to assess the relevance of clinical neuropsychology in screening methods considering older drivers population. The main goal is thus to study the contribution and the sensitivity of neuropsychological testing in the prediction of skills and habits of safe driving among older drivers. In the same vein, the thesis investigates the role of other socio-demographic and psychological variables.
To this end, article 1 evaluates the predictive validity of seven tests of visuo-attentional functions and working memory efficiency in relation to peripheral detection task performances in 50 drivers aged from 62 to 83 years in a simulated car driving environment. The driving simulation consisted of a simple driving condition and a condition including a "hands-free" cell phone distraction task. The results indicate that some neuropsychological tests, as opposed to age, are good predictors of detection performances. In addition, the predictive validity of the tests is more important in the most challenging driving condition. The Corsi Block Tapping test, assessing visuospatial working memory, is revealed as on of the best predictor of detection skills.
Article 2 was carried from previous neuropsychological testing and self-administered questionnaires related to avoidance driving behaviours, drivers perceptions and attitudes. The results indicate that individuals who show higher difficulties in tests assessing visuospatial working memory, processing speed, and divided and selective attention capacities are significantly more likely to adopt avoidance driving strategies. The results also demonstrate that driving avoidance is higher among drivers who tend to depreciate their general driving skills, to express a lower perception of control and an unfavourable attitude towards risky driving. Avoidance strategies are thus proven to be self-regulatory responses which are proportionate to cognitive limitations and individual perceptions.
In summary, this thesis demonstrates that peripheral detection performances of older drivers in a simulated car study, are well reflected in neuropsychological testing assessing working memory and other attentional abilities. Since detection skills are crucial for driving safety, an indirect link can be established between neuropsychological measures and road safety among older drivers. It also seems that those drivers, who have greater cognitive limitations, are more likely to avoid challenging driving situations, thereby balancing their crash risk. It is concluded that fitness-to-drive assessments based on neuropsychological screening need to be complemented with the assessment of self-regulatory behaviors. In the context of an aging population, new interventions should focus on strengthening self-regulatory behaviors of older drivers.